Urinary disorders, such as an inability to control urinary function, are common problems afflicting people of all ages, genders, and races. Various muscles, nerves, organs and conduits within the urinary tract cooperate to collect, store and release urine. A variety of disorders may compromise urinary tract performance and contribute to incontinence. Many of the disorders may be associated with aging or illness. Example urinary disorders include, for example, urgency and frequency disorders, urge incontinence, stress incontinence, and urinary retention disorders. Urgency and frequency disorders may involve the feeling of impending urination without the actual voiding of urine. Retention and voiding dysfunctions, for example, may involve the loss of urine and be at least partially attributable to injury or disease (e.g., a spinal cord injury). Some patients suffering from injury or disease that affects bladder function may not be able to void or have reduced levels of sensation when the bladder is full. These disorders may result in kidney damage and other complications.
In some cases, a urinary disorder may be at least partially attributable to improper sphincter function, either in the internal urinary sphincter or external urinary sphincter. For example, aging may result in weakened sphincter muscles, which may cause incontinence. Some patients also may suffer from nerve disorders that prevent proper triggering and operation of the bladder or sphincter muscles.
Electrical stimulation of nerves in the pelvic floor may provide an effective therapy for a variety of urinary (and, in some cases, fecal) disorders, including retention and voiding dysfunctions. For example, an implantable neurostimulator may be provided to deliver electrical stimulation to the sacral nerve to induce sphincter constriction and thereby close or maintain closure of the urethra at the bladder neck.